Distillation of a fluid mixture, e.g. air, into two or more portions enriched in a respective mixture component has generally been carried out employing one or more distillation or rectification columns which employ trays as the column internals or mass transfer elements. Recently there has developed an increasing use of structured packing as mass transfer elements in rectification columns because structured packing has a much lower pressure drop than does trays.
While structured packing has advantages over conventional trays in the operation of a distillation column, the cost of the packing is generally higher than that of the trays. The volume of packing required to effect a separation depends on the packing height and the column diameter. The latter is set by the capacity of the packing or equivalently by the flooding point wherein gas or vapor and liquid no longer effectively flow in countercurrent contact.
There has been developed structured packing which has increased capacity enabling increased column throughput before reaching flood conditions but such packing is generally characterized by having poor mechanical strength making it vulnerable to damage which compromises the increase in capacity.
Accordingly it is an object of this invention to provide a rectification system which utilizes structured packing which has higher capacity and also has higher mechanical strength than does heretofore available structured packing useful in rectification systems.